Can you find out the remainder when 3^300 is divided by 5?

Rectify the following equality 101 - 102 = 1 by moving just one digit.

Can you find the missing number in the third row?
35 20 14
27 12 18
5 2 ?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

Replace the question mark with the correct number, given the pair of numbers exhibits a similar relationship?

? : 3839 :: 11 : 1209

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

We have arranged an array of numbers below. What you have to do is use any kind of mathematical symbol you know excluding any symbol that contains a number like cube root. You can use any amount of symbols but you have to come up with a valid equation for all of them.

0 0 0 = 6
1 1 1 = 6
2 + 2 + 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

You have $100 with you and you have to buy 100 balls with it. 100 is the exact figure and you can't go below or above the numbers and you have to use the entire $100. If there is no kind of tax applied how many of each of the following balls will you be able to buy:

Green Balls costing $6
Yellow Balls costing $3
Black Balls costing $0.10

Now, how many of each must you buy to fulfil the condition given?

I guess 76.8% of readers will like this riddle.

What's the least number of people should read this post?

We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube?